What is it?
Nvidia Control Panel - NvCpl.dll

What does it do?
NvCpl.dll - This is loaded as a startup item. This loads the Nvidia Control Panel which is where you can tweak a ton of settings and overclock your card. Without this your drivers will be rather messed up and may or may not work properly.

This is a windows startup item.  If you're looking at your HJT log you will see a line that looks something like this:
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup

Virus Precautions:
You'll want to keep an eye on this google search for any known viruses. The normal location of this file is :\WINDOWS\system32\NvCpl.dll

More files in this category:

nwiz.exe | NvCpl.dll | ccApp.exe | savscan.exe | ccproxy.exe | hkcmd.exe | NvMcTray.dll | symlcsvc.exe | igfxtray.exe | qttask.exe | rtvscan.exe | SNDSrvc.exe | jusched.exe | nmain.exe | vsmon.exe | gearsec.exe | nvsvc32.exe | WZQKPICK.EXE | ati2evxx.exe | khooker.exe | Avserve.exe |